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ferdie avatar image
ferdie asked

Multiplus 12/1200VA Relay output usage for cooling fan?

Hi

Im planning on installing a Multiplus 12/1200VA inside a steel enclosure with a lithium battery.

The enclosure will be outdoor wall mounted and will receive sunlight in the afternoon. Im going to be adding a cooling fan to keep temperatures inside the case down. So ive read you can set the alarm relay to turn on when the multiplus internal fan turns on.

First question, what is the current rating for the relay? I cant seem to find a current rating for the relay anywhere? Id like to fit quite a large fan.

Second question, at what temperature does the internal multiplus fan come on? I want to avoid a situation where the multiplus is under no load so it doesn't deem it necessary to tun on its fan while the ambient temperature in the enclosure is lets say for arguments sake 60 degrees celcuis and busy cooking my lithium battery.

Third question, im going to have the external temp sensor of the multiplus mounted on the battery obviously. Would i be able to control the alarm relay using the battery temp reading?

MultiPlus Quattro Inverter ChargerRelayTemperature Sensorsystem designalarm
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Randall Shearer avatar image Randall Shearer commented ·

Have you found a definitive answer to your question?

I think I understand your question / scenario --> Can you connect cooling fans directly to the multiplus relay terminal, to be powered by that terminal, and triggered by the internal relay, linked to the internal cooling fan status via an Assistant. Such that, external fans will turn on & off with the multiplus fan.

I don't think this will work. I've been looking to do the same, and it seems that an external relay is needed.

It seems odd to me, but I think the system might be designed such that the relay in the multiplus shall be used to trigger an external relay that you'll provide with your fans, such that, your fans are powered by an external relay.

I hope I've go that wrong... as it seems unnecessary, especially if I don't need the internal relay for anything else. Unfortunately my knowledge is limited; I'm learning as I go. I thought adding external cooling fan would be simple.


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Alexandra avatar image Alexandra ♦ Randall Shearer commented ·

@Randall Shearer

You can up to a cartain volt amp range (mentioned in the tech specs in the manual)

Is it advised? It is better to use the internal relays to signal another relay that carries the current for running the fans. Mistakes happen it is better to protect the internals.

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Randall Shearer avatar image Randall Shearer Alexandra ♦ commented ·
Thank you! I'd previously read the manual (several times) but didn't understand how to use the relay... Your message spurred me to study each page more carefully... and I found it. I've now got few small fans cooling the space where the Multiplus is situated. Thanks again!
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3 Answers
Alexandra avatar image
Alexandra answered ·

@Ferdie

The internal fans run when:-

1. There is some heavier charging going on from grid/ac pv.

2. The load is higher or a heavier load switches on more pronounced when inverting.

3. When the internal temps start going above 30°C or about there.

The relays are designed to signal other things/relays rather like a PLC, not so much run the load. If they are like the rest of the inverter ranges, it is less than 100mA. Also depends on the voltage your fan is as well as to whether you want to pass that through the relay.

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ferdie avatar image ferdie commented ·
Well the fan ive landed on is 12vdc and draws 0.9A. So ill get the power for the fan through a fuse from the battery and just use the relay to switch that. Im sure a relay that is rated at 4A 32VDC will be able to handle 0.9A at 12VDC.
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klim8skeptic avatar image
klim8skeptic answered ·

First question, what is the current rating for the relay? I cant seem to find a current rating for the relay anywhere? Id like to fit quite a large fan.

The newer plastic shelled multi 12-1200, has the following relay rating. I suspect the previous multi compact has the same relay ratings, do confirm that though.

multiplus-12-1200-relay.png

Second question, at what temperature does the internal multiplus fan come on? I want to avoid a situation where the multiplus is under no load so it doesn't deem it necessary to tun on its fan while the ambient temperature in the enclosure is lets say for arguments sake 60 degrees celcuis and busy cooking my lithium battery.

From my experience with a compact multi 12-1600, the internal fan will run at ambient temps around 40c+, at no (or very low) output. That seems logical, as the internals are generating heat, even under no load.

Third question, im going to have the external temp sensor of the multiplus mounted on the battery obviously. Would i be able to control the alarm relay using the battery temp reading?

If you use the relay to control an external fan, any alarm would occur when the fan(s) run.



multiplus-12-1200-relay.png (179.9 KiB)
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ferdie avatar image
ferdie answered ·

Thanks

For the last question i was referring to the relay incorrectly. It wont be connected to an alarm at all, the relay will only switch the fan. So just to clarify what i meant: Will i be able to control the programmable relay using a reading from the battery temp sensor?

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Time to use the search function.

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